多级孔-规整型-金属氧化物和纳米碳管复合物的制备及其在催化中的应用

The key challenge for fuel cell oriented hydrogen production is to develop compact and miniaturized hydrogen production reactor. On this area, researches in literatures mainly concentrated on micro-reactor with channel size of several hundred micron meter. However, its size is still too bulky. In recent years, we have studied new route for the miniaturization of the reactor, that is to prepare macroporous monolithic catalyst with pore size in the range of tens nanometer to tens micron meter. The results showed that this is a highly potential route for the miniaturization. Yet, improvement is needed for this new route. The catalyst support of the macroporous monolith is made of oxide, namely alumina, silica or titania, their thermal conductivity is poor. The poor thermal conductivity is prone to form hot spots on the catalyst surface as the catalyst catalyzing exothermic reaction. The hot spots can generate side reactions, which are harmful to the hydrogen production reactions. In this project, we will introduce carbon nanotubes (CNTs) into the monolithic support to improve its thermal conductivity. To study the preparation of the composite of macroporous monolithic CNTs-oxides; to study loading mesoporous oxide and nano catalyst on the walls of the macropores; to study the properties of the composite and relationship between the properties and the preparation conditions. Take preferentail oxidation of CO in hydrogen rich gases as the representative reaction, to study the miniaturization effect and the related michanism. The mesopore leads to high surfase area, the macropore favours mass and heat diffusion, addition of CNTs can improve thermal and electrical conductivity and mechanical strength, the monolith can be any wanted shape which is flexible for utilization. Thus, the studied composite material in this project, the meso-macroporous monolithic CNTs-oxides, is a novel and valuable and potentially can be used in extensive areas.

氢-燃料电池的制氢系统面临的关键问题是"小/微型化"，目前文献报道的解决对策是采用孔径几百微米的微型催化反应器，但体积仍然太大。我们近年来提出和研究的新途径是将催化剂制成孔径在几十纳米至几十微米的大孔结构和规整型，并证实这是很有前景的途径。这个新途径面临的关键问题：大孔规整催化剂的载体是氧化物，导热性差，导致催化剂表面容易形成热点；热点上容易发生副反应，严重影响催化转化效率。本项目拟将导热性能优越的纳米碳管（CNTs）复合进入此催化剂载体，以提高导热性。将研究大孔-规整型CNTs-氧化物复合物的制备化学，大孔壁上构筑介孔氧化物和催化剂组分，研究所制备材料的性质及其与制备的关系。以CO优先氧化为代表反应，研究"小/微型化"效果和其中的机理。介孔有高比表面，大孔利于传质，复合CNTs可提高导热、导电性能和机械强度，规整型则应用灵活，所以拟研究的"多级孔-规整型-CNTs-氧化物"应用潜力很大。

氢-燃料电池的制氢系统面临的关键问题是"小/微型化"，目前文献报道的解决对策是采用孔径几百微米的微型催化反应器，但体积仍然太大。本课题组提出和研究的新途径是将催化剂制成孔径在几十纳米至几十微米的大孔结构和规整型，实验结果证实这是很有前景的途径。这个新途径面临的关键问题：大孔规整催化剂的载体是氧化物，导热性差，导致催化剂表面容易形成热点；热点上容易发生副反应，严重影响催化转化效率。本项目将导热性能优越的石墨烯（GS）、纳米碳管（CNTs）或碳纤维（CFs）复合进入该催化剂载体，以提高导热性。研究了大孔-规整型GS（或CNTs或CFs）-氧化物复合物的制备化学、大孔壁上构筑介孔氧化物和催化剂组分，研究了所制备材料的性质及其与制备的关系。以CO优先氧化为代表反应，研究了"小/微型化"效果和其中的机理。催化剂上形成热点是大部分放热反应面临的问题，该复合催化剂设计思路用于合成气制低碳醇（强放热反应）也取得了良好的效果。介孔有高比表面，大孔利于传质，复合GS、CNTs或CFs可提高导热、导电性能和机械强度，规整型则应用灵活，所以本项目提出和研究的"多级孔-规整型-GS/CNTs/CFs-氧化物"催化材料拓展了催化剂设计途径和思路。发表标注了本基金资助的SCI论文32篇，其中一区和二区论文合计25篇；申请专利3项，其中授权1项。在第十八届全国催化大会上作了邀请报告，参加了其他一些国际国内学术会议。